I have a 1998 F-150 and I am having problems with the wipers. It will work on low and high speed but they won't work on any of the other speeds. I know that it has to have some kind of variable speed control but I don't know where it is located in the truck. I have checked all relays and fuse's and it's all good I even replaced the turning signal swith Thinking that the switch had gone bad.

If anyone can help Please do ( It sucks when it rains guys I need help)

Thanks Hector

 

Have you checked the voltage on the wiper motor on the intermittent setting ? You may have a bad wiper motor

 

No I have not thats good thinking. What should the voltage be at the motor?

 

well on high it should be a constant twelve volt maybe a little more or less and with them on low you should see it pulsate when the wipers move to twelve volts and so on and so forth the slower the wipers are the slower the voltage will pulsate